Bicyclic imidazoles and pyrimidines

ABSTRACT

Compounds of the class of imidazo(1,2-a)imidazoles, imidazo(1,2a)pyrimidines and pyrimido(1,2-a)pyrimidines useful as central nervous system (CNS) antidepressants; and certain novel precursors therefor.

United States Patent [1 1 Van Gelder et a1.

1 1 BICYCLIC IMIDAZOLES AND PYREMIDKNES [75] Inventors: Josephus Ludovicus Hubertus Van Gelder; Alfons Herman Margaretha Raeymaekers, both of Beerse; Leopold Frans Comeel Roevens, Rijkevorsel; Willey Joannes Van Laerhoven, Ravels, all of Belgium [73] Assignee: Janssen Pharmaceutica N.V.,

Beerse, Belgium [22] Filed: Aug. 13, 1974 1 [21] Appl. No.2 499,743

Related U.S. Application Data [62] Division of Ser. No. 313,285, Decv 8, 1972, Pat. No,

US. Cl ..260/256.4 F; 260/2564 H; 260/2564 N; 260/3096; 260/3097; 260/5705 P; 260/5705 R:

[51] Int. Cl. C07D 239/00 [58] Field of Search 260/2564 F Dec. 9, 1975 {56} References Cited FOREIGN PATENTS OR APPLICATIONS 796,996 6/1958 United Kingdom 260/3096 805,877 12/1958 United Kingdom 260/3096 Primary Examiner-Paul M. Coughlan, Jr. Assistant Examiner-James H. Turnipseed Attorney, Agent, or FirmSalvatore R. Come [57] ABSTRACT Compounds of the class of imidazoH ,2-a]imidazoles. imidazo[ l ,2-a]pyrimidines and pyrimid0[ 1 ,2- a]pyrimidines useful as central nervous system (CNS) antidepressants; and certain novel precursors therefor.

2 Claims, N0 Drawings BICYCLIC IMIDAZOLES AND PYRIMIDINES CROSS-REFERENCE TO RELATED APPLICATION This is a divisional application of my co-pending application Ser. No. 313,285, filed Dec. 8, 1972 now US. Pat. No. 3,865,836.

BACKGROUND OF THE INVENTION PREFERRED EMBODIMENTS The novel bicyclic imidazoles and pyrimidines of this invention may be structurally represented by the following formula:

The compounds of formula (I) are conveniently prepared by ring closure of an appropriate precursor of formula (II) in which the symbols Ar, m, n, R and R, are as previously described. Such ring closure is readily accomplished by treatment with concentrated sulfuric acid or with thionyl chloride and base, e.g., sodium:

Ar (6 23; To

2 n K (I) it 1 f NH OH (CH2 l l. cone. H 501,

N i";i 2 n 2. S0012; Na

wherein m is the integer zero or 1; 5 wherein n is the integer zero or I; wherein R is a member selected from the group consisting of hydrogen and benzyl; N 1 wherein R, is a member selected from the group conr sisting of hydrogen and loweralkyl, preferably l )3 methyl, provided that, when said R, is loweralkyl, g Rl then said n is zero; and wherein Ar is a member selected from the group consisting of phenyl, loweralkylphenyl, halophenyl and dihalophenyl.

The therapeutically active non-toxic acid addition salts of the foregoing compounds (I) are also embraced within the scope of this invention.

As used herein, loweralkyl may be straight or branch chained and have from 1 to 5 carbon atoms, such as, for example, methyl, ethyl, propyl, isopropyl, butyl, text-butyl, pentyl and the like alkyls. The preferred loweralkyl is methyl. The term halo" refers to halogens of atomic weight less than 127, i.e., chloro, bromo, fluoro and iodo.

When R is hydrogen, the subject compounds (I) exhibit tautomerism due to the migration of the corresponding proton between the two nitrogens as follows:

The compounds of formula (II), wherein R is hydrogen, are conveniently prepared by the reaction of an appropriate 2-nitroamino-imidazoline or 2-nitroaminotetrahydro pyrimidine of formula (III), wherein m is the integer zero or 1, with an appropriate a-(aminoalkyl)- benzyl alcohol of formula (IV), wherein n, R, and Ar are as previously defined, in a suitable inert organic solvent. Typical solvents that may be employed are aromatic hydrocarbons, e.g., benzene, toluene, xylene and the like, and ethers, e.g., dioxane and monoethyl and diethyl ethers of ethane diol. Elevated temperatures may be employed to enhance the rate of reaction. The foregoing reactions may be illustrated as follows:

To prepare the compounds of formula (II), in which R is benzyl, an appropriate 2-benzylamino-imidazoline anol of formula (XI), wherein m is the integer zero of l, in a suitable inert organic solvent and, preferably, in

or Z-benzylamino-pyrimidine of formula (Vi), wherein 20 the cold (0-5C). The thus-obtained nitro-alcohol m is zero or 1, is reacted with an appropriate methyl base of formula (XII), which may be conveniently isolk l h lid f bl th b id f f la (VII) lated by conventional transformation into an acid addiwherein Ar and n are as previously described, in a suith Salt, for x mple, by treatment with alkahohc L able organic solvent such as, for example, an aromatic 25 15 then Subjected to catalytic hydrogenation to afford hydrocarbon, e.g benzene, toluene, xylene and the the corresponding of formula like, an ether,e.g., dioxane, diethyl ether, tetrahydrofuwhich y also be Similarly isolated in the form o an ran and the like, and a lower alkanone, e.g., acetone, acid addition The latter Compound is methyl ethyl kemne and the m If desired, a Smichiotreated with carbon disulfide to thereby effectuate ring metric excess f basic (VI) a ha|ogen acid Scavenger 3O closure and yield the 2-thio-3-imidazolidine alkanol of may be added to pick up the halogen acid that is hep formula (XIV). Transformation of the latter into the ated during the course of the reaction. The carbonyl correspohdlhg ZmCthYhhiO-Ti-imidal0line ol of function of the thus-obtained condensation product (Xv) acccmphshed y conventional methyl (vm) is reduced to a carbinol function (IX) by p iodide treatment. The 2-methylthio function is tranment with suitable reducing agents, such as sodium 35 fofmed z'ammo fuhctiOh X V y treatment borohydride and the like. The foregoing reactions are l The y y function is replaced With a musuated as f ll chloro function (XVII) by treatment with thionyl chloride, preferably at reflux temperatures in a suitable or- I NH a n L Br-IiH-(CH C acetone (VI) (VII) NaBHu m c H Ii-CH(R )-(CH ZH-Ar p B An alternative method of making the imidazo{l,2- a]imidazolines and imidazoll,2-a]pyrimidines of formula (I), wherein n is 0 and R=R,=hydrogen, is through the following synthetic sequence. An appropriate nitrostyrene of formula (X), wherein Ar is as previously defined, is reacted with an appropriate aminoalkganic solvent such as, for example, chloroform. Ring 5 closure into the desired bicyclic product (XVIII) is accomplished by treatment with alkali metal, e.g., sodium, in a suitable solvent, e.g., methanol, under reflux. The foregoing reaction sequence may be schematically illustrated as follows:

8 H H N Y N N N Ar I N 2) :tautomerism. Ar 2 )m (XVIII) (XVIII) The subject compounds of formula (I) have been TABLE I found to possess useful pharmacological properties as demonstrated in one or more of the following tests incompoundAmphemmine g fgzgi l i 3 t t e O dlcauve of CNS antidepressant yof Ex. test-dose palp.ptosis hypotherdeferens No. in mglkg mg/kg mia mg/kg mg/liter 11 2.5 0.16 0.01; 0.0025 Ill 10 0.16 0.31 0.04 IV 10 0.31 0.31 0.01 I v 2.5 0.16 0.63 0.16 Test A. Amphetamine test in rats: v1 ,10 0.04 0.16 0.04 v11 10 0.63 0.63 0.01 An intravenous lnJeCtlOll of 5 mg/kg of dextroamv1|1 10 0.63 0.63 0.01 phetamine in rats induces pronounced CNS-stimulating a -3 g 5 3%: effects that are characterized by stereotyped chewing Xl m movements, agitation and exophtalmia. These effects XI! 10 0.16 0.63 0.04 last for about 1 to likhour after treatment. Pretreat- [B 8:23 g'g: ment with antidepressants give a prolongation of these XV-a 2.5 0.16 0.31 0.0025 typical effects which are still observable up to 4 hours after the injection of dextroamphetamine. The dose level at which the tested compound potentiates these effects of amphetamine is recorded.

Test 8. Anti-tetrabenazine activity in mice:

A subcutaneous injection of 10 mg/kg of Ro-4-l284 (a tetrabenazine-like compound) produces significant palpebral ptosis and hypothermia in mice. All known anti-depressants antagonize these effects when given before the challenging dose of Ro-4-l284. The lowest significant subcutaneous dose level at which the tested compound antagonizes the palpebral ptosis and the hypothermia, respectively, is recorded.

Test C. Test on vas deferens of the rat:

A vas deferens is isolated and suspended in a 10 0 ml Tyrode-bath. Contractions are recorded on a Kymograph. Following a stabilization time of 15 minutes, noradrenaline is added to the bath-solution at 6- minutes intervals. The drug to be tested is added to the Tyrode-solution and the interaction with noradrenaline-induced contractions is measured. Drug effect is called potentiation if the noradrenaline-induced contraction obtained in the presence of the drug exceeds the response to noradrenaline previously obtained. The dose of the drug, expressed in mg per liter, which potentiates the noradrenaline response is recorded.

In the following table, the CNS antidepressant profile of several of the subject compounds is listed, as demonstrated by their relative responses to the aforementioned tests. it is understood that the compounds listed therein are not stated for purposes of limiting the invention thereto, but only to show the useful properties 6 of all the compounds within the scope of formula (I).

a dextro isomer of Example I Compound b levo isomer of Example I Compound Due to the assymetric carbons present in the subject compounds (1), it is evident that their existence in the form of stereochemical isomers (enantiornorphs) is possible. if desired, the resolution and isolation or the production of a particular form can be accomplished by application of general principles and techniques known in the art. Such pharmacologically active enantiomorphs are naturally intended to be includes within the scope of this invention.

The organic bases of formula (I) may be converted to the corresponding pharmaceutically acceptable acid addition salts by reaction with an appropriate inorganic acid, such as, for example, hydrochloric, hydrobromic, hydriodic, sulfuric and the like acids, or with an appropriate organic acid, such as, for example, acetic propionic, glycolic, lactic oxalic, malonic, tartaric, citric, sulfamic, ascorbic and the like acids. in turn, the acid addition salts may be converted to the corresponding base form by conventional treatment with suitable alkali.

The preferred compounds herein are those of formula (I) in which m and 11 both equal zero, and R and R both equalhydrogen, which compounds may be illustrated by the formula:

Giff

and denoted as 2,3,5,6-tetrahydro-3(5)-Ar-ll-I- imidazo[1,2-a]imidazoles. The most preferred species are those in which Ar is phenyl and fluorophenyl.

The compounds of formulas (II) and (VIll) are deemed to be novel and, in view of their utility as precursors in the snythetic procedures previously described, such compounds constitute an additional feature of this invention.

The following examples are intended to illustrate and not to limit the scope of the present invention. Unless otherwise stated, all parts are by weight.

EXAMPLE I A mixture of 15.8 parts B-hydroxy-phenethyl-amine, 13 parts Z-nitramino-Z-imidazoline and 8 parts xylene is stirred and heated for 30 minutes at 160C. (oilbath). After cooling the reaction mixture to a temperature of about 70C., there are added 40 parts acetone. The whole is filtered warm and after cooling the filtrate to room temperature, the precipicated product is filtered off and dried, yielding Z-(B-hydroxy-phenethylamino)-2-imidazoline; m.p. l47-l49C.

To 80 parts thionylchloride (previously cooled to C.) are added 10.15 parts Z-(B-hydroxy-phenethylamino)-2-imidazoline. After the addition is complete, the whole is stirred for 30 minutes at room temperature and further stirred and refluxed for 15 minutes. The solvent is evaporated. The residue is dissolved in 40 parts toluene and evaporated again. This treatment is repeated by using 40 parts methanol. The residue is then dissolved in 40 parts Z-propanol. To this solution is added a solution of 1.15 parts sodium metal in 40 parts 2-propanol. The whole is stirred and refluxed for one hour. The solvent is evaporated. The residue is dissolved in 150 parts water. The solution is filtered. The filtrate is alkalized with ammonium hydroxide and extracted three times with 40 parts ether and three times with 75 parts chloroform. The combined extracts are dried over potassium carbonate and evaporated. The solid residue is recrystallized from a mixture of 16 parts acetone and 16 parts 4 -methyl-2-pentanone, yielding 2,3 ,5 ,dtetrahydro-S-phenyl-l l-l-imidazo[ 1 ,2- a]imidazole; m.p. 167169.5C.

EXAMPLE 11 Three parts of 2-(B-hydroxyphenethylamino)-2- imidazoline are added portionwise to 1 1 parts of concentrated sulfuric acid solution at 0C. The whole is stirred at room temperature for 2 hr. 30 minutes and poured onto crushed ice. The formed precipitate is filtered off and the filtrate is alkalized with sodium hydroxide. The product is extracted three times with chloroform (once with 75 parts and twice with 150 parts). The combined extracts are dried and evaporated. The residue is triturated in acetone, treated with activated charcoal, filtered and the filtrate is evaporated. The residue is converted into the hydrochloride salt in 4-methyl-2-pentanone. The precipitated salt is filtered off, washed with 2-propanol and dried, yielding 2,3,5 ,6-tetrahydro-5-phenyll H-imidazo[ 1,2- a]imidazole hydrochloride, m.p. 227.5229C.

10 EXAMPLE m A mixture of 6.5 parts of a-( l-aminoethyl)benzyl alcohol (also known as morephedrine), 5.2 parts of 2- (nitramino)-2-imidazoline and 8 parts of xylene is stirred for 30 minutes while heating at 160l70C. The reaction mixture is cooled and diluted with acetone. The latter is removed in vacuo, yielding a-[ l-(2- imidazolin-Z-ylamino)-ethyl]benzyl alcohol as an oily residue.

A solution of 12 parts of the oily a-[ I-(Z-imidazolin- 2-ylamino)ethyl]benzyl alcohol in 40 parts of sulfuric acid solution is stirred for 3 hours at room temperature. The reaction mixture is poured onto crushed ice. The whole is alkalized with sodium hydroxide solution and the product is extracted with toluene. The extract is dried, filtered and evaporated. The residue is washed with acetone and dried, yielding 2,3,5,6-tetrahydr02 methyl-B-phenyl- 1 H-imidazo[ 1,2-a]imidazole; m .p. 179.4C.

EXAMPLE 1V imidazolin-Z-ylaminomethyl)benzyl alcohol; m.p. 148C.

4.3 parts of 3,4-dichloro-a-(2-imidazoline-2- ylarninomethyl)benzyl alcohol are added portionwise to 16.2 parts of sulfuric acid solution 80% while stirring and cooling. Upon completion, the mixture is stirred for 2 hr. 30 min. at room temperature. The reaction 40 mixture is poured onto ice-water, alkalized with concentrated sodium hydroxide solution and the product in base form is extracted with methylene chloride. The organic layer is dried, filtered and evaporated. The residue is converted into the hydrochloride salt in 2- 45 propanol, yielding 5-(3,4-dichlorophenyl)-2,3,5,6-tetrahydro-1H-imidazo[ l,2-a]imidazole m.p. 298 .4C (dec.

hydrochloride;

EXAMPLE V To a solution of 6.5 parts of a-(aminomethyl)-pfluorobenzyl alcohol in 8 parts of xylene are added 5.2 parts of 2(nitramino)-2-imidazoline. The mixture is heated in an oil-bath to about C. till gas-evolution is ceased (about 15 minutes). The reaction mixture is cooled and treated with benzene and acetone. The product is sucked off and crystallized from 4-methyl-2- pentanone, yielding p-fluoro-a-(2-imidazolin-2- ylaminomethyl)benzyl alcohol; m.p. 153.4C.

To 18 parts of sulfuric acid 80% are added portionwise 2 parts of p-fluoro-a-(2-imidazolin-2-ylaminomethyl)benzyl alcohol while cooling and stirring in an icebath. Upon completion, stirring is continued for 2 hr. 15 min. at room temperature. The reaction mixture is 65 poured onto ice-water, diluted with water till a volume and evaporated. The residue is converted into the hydrochloride salt, yielding S-(p-fluorophenyl)-2,3,5,6- tetrahydro-lH-imidazo[1,2-a1imidazole hydrochlo ride; m.p. 259.8C.

EXAMPLE VI To 5.2 parts of 2--(nitramino)-2-imidazoline is added a solution of 7.5 parts of a-(aminomethyl)-pchlorobenzyl alcohol in 40 parts of xylene while heating. Upon completion, stirring is continued while heating in an oil-bath at l50l60C. and while the xylene is partly distilled off (till gas evolution ceases). The residue is cooled and after the addition ofa few parts of acetone, the product is allowed to crystallize. It is filtered off, washed successively with acetone and diisopropylether, dried and the product is recrystallized from 4-methyl-2-pentanone, yielding p-chloro-a-(Z- imidazolin-2-ylaminomethyl)benzyl alcohol; m.p. l56-l58C.

3.4 parts of p chloro-a-(2-imidazolin-2-ylaminomethyl)benzyl alcohol are added to 30 parts of sulfuric acid 80% while stirring and cooling in an ice-bath. Upon completion, the whole is stirred for 2 hours at room temperature. The reaction mixture is poured onto crushed ice, alkalized with a concentrated sodium hydroxide solution and the product in base form is extracted with methylene chloride. The extract is dried, filtered and evaporated. The residue is dissolved in 2- propanol. The solution is filtered over diatomaceous silica and the filtrate is acidified with an excess of 2- propanol previously saturated with gaseous hydrogen chloride. The precipitated salt is filtered off, washed with acetone and dried, yielding 5-(p-chlorophenyl)- 2,3,5 ,-tetrahydrol H-imidazo( l ,2a]imidazole hydrochloride, m.p. 266.1C.

EXAMPLE Vll A mixture of 8.2 parts of a-(aminomethyl)-m-methylbenzyl alcohol, 6,1 parts of 2-(nitramino)-2-imidazoline and 40 parts of xylene is stirred in an oil-bath at l50-l60C, while almost all xylene is distilled off. The residue is diluted with a few parts of acetone and allowed to crystallize. The product is filtered off and recrystallized from 4-methyl-2-pentanone, yielding a-(2- imidazolin-Z-ylarninomethyl)-m-methylbenzyl alcohol; m.p. l2lC.

4 parts of a-(2-imidazolin-2-ylaminomethyl)-mmethylbenzyl alcohol are added portionwise to 36 parts of sulfuric acid solution 80% while cooling in an icebath. The mixture is stirred for 2 hours at room temperature. The reaction mixture is poured onto crushed ice and the resulting solution is alkalized with sodium hydroxide solution at room temperature (cooling with ice is necessary). The product in base form is extracted with chloroform. The extract is converted into the hydrochloride salt in 2-propanol, yielding 2,3,5,6,-tetrahydro-5'm-tolyl-lH-imidazo[1,2-a]imidazole hydrochloride; m.p. 269.lC. (dec.).

EXAMPLE Vlil A mixture of 9.5 parts of a-(aminomethyl)-m-chlorobenzyl alcohol, 7.15 parts of 2-(nitramino)-2-imidazoline and 40 parts of xylene is stirred in an oil-bath at l50l60C. while a great part of the xylene is distilled off. The resulting residue is diluted with a few parts of acetone and the product is allowed to crystallize. It is filtered off and crystallized from 4-methyl-2-pentanone, yielding m-chloro-oz-(2-imidazolin-2-ylaminomethyl)benzyl alcohol; m.p. 108.5C.

4 parts of m-chloro-a-(Z-imidazolin-2-ylaminomethyl)-benzyl alcohol are added portionwise to 20 parts of cooled (ice-bath) sulfuric acid solution Upon completion, the whole is stirred for 2 hours at room temperature. The reaction mixture is poured onto crushed ice and the whole is filtered over diatomaceous silica. The filtrate is alkalized with ammonium hydroxide solution at room temperature (cooling is necessary) and the product in base form is extracted with chloroform. The latter is dried and evaporated. The residue is converted into the hydrochloride salt in 2-propanol, yielding 5-(m-chlorophenyl)-2,3,5,6-tetrahydrolH- imidazo[ l ,2-a]imidazole hydrochloride; m.p. 249.8C.

EXAMPLE IX A mixture of 9.06 parts of a-(aminomethyl)-p-methylbenzyl alcohol, 7.8 parts of 2-(nitramino)-2-imidazoline and 8 parts of xylene is stirred for 30 minutes at 160C (oil-bath). The reaction mixture is cooled and acetone is added. The precipitated product is filtered off, washed with acetone and dried, yielding a-(2- imidazolin-Z-ylaminomethyl)-p-methylbenzyl alcohol; 163.7C.

A solution of 5 parts of a-(2-imidazoline-2- ylaminomethyl)-p-methylbenzyl alcohol in 45 parts of concentrated sulfuric acid is stirred overnight at room temperature. The reaction mixture is poured onto water, alkalized with sodium hydroxide and the product is extracted with toluene. The extract is dried and evaporated. The oily residue is stirred in acetone and the solid base product is filtered off. it is converted into the hydrochloride salt in 2-propanol, yielding 2,3,5,6-tetrahydro-3-p-tolyl-l l-l-imidazo [l,2-a]imidazole hydrochloride; m.p. 254.2C.

EXAMPLE X A mixture of 7.2 parts of l,4,5,6-tetrahydro-2- nitraminopyrimidine, 7.55 parts of a-(aminomethyhbenzyl alcohol and 12 parts of xylene is stirred and refluxed for 4 hours on a water-tap. The xylene is evaporated and the residue is dissolved in 20 parts of acetone. The product is crystallized at room temperature. It is filtered off and dried, yielding a-( l ,4,5,6,-tetrahydro-2-pyrimidinylaminomethyl)benzyl alcohol.

4.4 parts of a-( l,4,5,6-tetrahydro-2- pyrimidinylaminomethyl)benzyl alcohol are stirred and cooled to 0C. While keeping the temperature 0C, there are added portionwise l6.5 parts of sulfuric acid solution 80%. Upon completion, the whole is stirred for 2 hr. 30 minutes at room temperature. The reaction mixture is poured onto crushed ice, treated with activated charcoal, filtered and the filtrate is made strongly alkaline with a ION sodium hydroxide solution. The product is extracted with methylene chloride (three times 40 parts). The extract is dried and evaporated. The solid residue is treated with a small amount of acetone and the product in base form is filtered off again and converted into the hydrochloride salt of 2,3,5,6,7,8-hexahydro-3-phenylimidazo[1,2-a1pyrimidine; m.p. 188C.

EXAMPLE X] -a] To a stirred solution of 13.9 parts of 2,4- dibromoacetophenone in parts of acetone are added portionwise 8.75 parts of 2-(N-benzylamino)-2- imidazoline. Upon completion, stirring is continued for 13 2 days at room temperature. The precipitated product is filtered off, washed with acetone, dried and crystallized from ethanol, yielding 2-[N-benzyl-N-(Z-imidazolin-2-yl)amino]-4'-bromoacetophenone hydrobromide, m.p. 262.9C.

To a stirred suspension of 5.5 parts of 2-lN-benzyl-N- (2-imidazolin-2-yl)amino1-4'-bromoacetophenone hydrobromide in 80 parts of ethanol is added portionwise 0.45 parts of sodium borohydride at room temperature. Upon completion, stirring is contined overnight (about 16 hours). The reaction mixture is diluted with 50 parts of water and the ethanol is distilled off in vacuo. The residue is extracted with chloroform. The latter is dried and evaporated. The residue is converted into the hydrochloride salt in Z-propanol, yielding a-[N-benzyl-N- (2-imidazolin-2-yl)aminomethyl]-p-bromobenzylalcohol hydrochloride hemiisopropyl alcoholate, m.p. 148.4C.

A mixture of 1.87 parts of a-[N-benzyl-N-(2- imidazolin-Z-yl)aminomethyll-p-bromobenzylalcohol and 27 parts of sulfuric acid 80% is stirred for 2 hours at room temperature. The reaction mixture is poured onto crushed ice. The whole is alkalized with sodium hydroxide solution and the product in base form is extracted with toluene. The latter is dried, filtered and evaporated. The residue is converted into the oxalate salt in 2-propanol. The crude salt is filtered off and crystallized from 2-propanol, yielding l-benzyl-3-(pbromophenyl)-2,3,5 ,6-tetrahydro-l I-I-imidazo[ 1,2- a]imidazole oxalate, m.p. l44.8C.

EXAMPLE XII A mixture of 8 parts of a-(Z-aminoethyl)benzylalcohol, 6.5 parts of 2-(nitramino)-2-imidazoline and 40 parts of xylene is stirred and refluxed for 3 hours with water-separator. The reaction mixture is cooled and the separated oily product is dissolved in 4-methyl-2- pentanone. The solvent is evaporated in vacuo, yielding a-{ 2-[N-(2-imidazolin-2-yl)amino]} benzylalcohol as a residue.

A mixture of 8 parts of a-{ 2-[N-(2-imidazolin-2- yl)amino]ethyllbenzylalcohol from the preceding step and 36 parts of sulfuric acid 80% is stirred for 3 hours at room temperature. The reaction mixture is poured onto crushed ice and the resulting solution is allowed to stand overnight at room temperature. It is then alkalized with sodium hydroxide solution and the product is extracted with toluene. The extract is dried, filtered and evaporated. The residue is triturated in acetone. The solid product is filtered off and crystallized from acetone, yielding 2,3,5,6,7,8-hexahydro-5- phenylimidazo[ l ,2-a]pyrimidine; m.p. l45.5C.

EXAMPLE XIII A mixture of 8 parts of a-(2-aminoethyl)benzylalcohol, 7.2 parts of 2-(nitramino)-l,4,5,6-tetrahydropyrimidine and 40 parts of xylene is stirred and refluxed for 48 hours with water-separator. Upon cooling the reaction mixture, the product is separated as an oil. The xylene is decanted and the oily product is triturated in diisopropylether. The solid product is filtered off and crystallized from acetone, yielding a-[Z- l ,4,5,G-tetrahydro-Z-pyrimidinylamino)ethyl]benzylalcohol; m.p. l30l35C.

A mixture of 2 parts of az-[2-(l,4,5,6-tetrahydro-2 pyrimidinylamino)ethyllbenzylalcohol and 27 parts of sulfuric acid 80% is stirred for 2 hours at room temperature. The reaction mixture is poured onto crushed ice and the whole is alkalized with sodium hydroxide solution. The product is extracted with toluene. The organic layer is separated, dried, filtered and evaporated. The solid residue is crystallized from acetone, yielding 3,4,6,7,8,9-hexahydro -6phenyl-2H-primido[ 1,2- alpyrimidine, m.p. l77-l79C.

EXAMPLE XIV A solution of 6.1 parts of 2-aminoethanol in 16 parts of methanol and 40 parts of ether is cooled on ice. Then there is added dropwise at about 5C. a solution of l8.4 parts of o-chloro-a-nitrostyrene in 60 parts of ether. Upon completion, stirring in an ice-bath is continued for one hour. The reaction mixture is acidified with an excess of 2-propanol previously saturated with gaseous hydrogen chloride. The precipitated product is filtered off, washed thoroughly with ether and dried, yielding 2-{N-[o-chloro-a-(nitromethyl)benzyllamino }ethanol hydrochloride.

To a mixture of 26 parts of 2-{N-[o-chloro-a-(ni tromethyl)benzylamino} ethanol hydrochloride and 2 parts of Raney-Nickel catalyst is added parts of methanol (cooled in a mixture of methanol/carbon dioxide), followed by the addition of 20 parts of carbon dioxide. The whole is hydrogenated at 50 lbs/sq. inch pressure over 2 hours. The catalyst is filtered off and the filtrate is acidified with an excess of Z-propanol pre viously saturated with gaseous hydrogen chloride. The precipitated salt is filtered off, washed with methanol and dried, yielding 2-{N-[a-(aminomethyl)-ochlorobenzyl1amino} ethanol dihydrochloride.

To a stirred mixture of 5.75 parts of 2{N-[a- (aminomethyl)-o-chlorobenzyl]amino} ethanol dihydrochloride, 8 parts of ethanol and 6 parts of water is added 4 parts of sodium hydroxide solution lON. To the resulting clear solution are added dropwise L68 parts of carbon disulfide and the whole is stirred and refluxed for one hour. After the addition of 0.2 parts of hydrochloric acid solution ION, stirring and refluxing is continued for 5 hours. The reaction mixture is cooled to room temperature and the precipitated product is filtered off. It is washed successively with a mixture of water and ethanol (1:1 by volume), with ethanol and with water, and dried. The product is crystallized from ethanol, yielding 4-(o-chlorophenyl)-2-thio-3- imidazolidineethanol; m.p. I69. 1C.

A mixture of 12.84 parts of 4-(o-chlorophenyl)-2- thio-3-imidazolidineethanol, 7.81 parts of methyl iodide and 40 parts of methanol is stirred for 4 hours at 40C. Diisopropylether is added and the solvent is decanted, yielding 5-(o-chlorophenyl)-2-(methylthio)-2- imidazoline-l-ethanol hydroiodide as an oily residue.

A mixture of l8.3 parts of 5-(o-chlorophenyl)-2- (methylthio)-2-imidazolinel-ethanol hydroiodide and 40 parts of methanol saturated with ammonia is stirred and refluxed for 2 hours. The solvent is evaporated and the solid residue is treated with 20 parts of 2-propanol. The product is filtered off and recrystallized form 50 parts of water, yielding 2-amino-5-(o-chlorophenyl)-2- imidazoline-l-ethanol hydroiodide, m.p. 181.6C.

A mixture of 4.15 parts of 2-amino-5-(o-chlorophenyl)-2-imidazoline-l-ethanol hydrochloride in 22.5 parts of chloroform is treated with 3.6 parts of thionyl chloride and the whole is stirred at reflux temperature for 30 minutes. The solvent is evaporated and the residue is taken up in 15 parts of chloroform. The latter is evaporated again, yielding Z-amino-l-(2-chloroethyl)- S-(o-chlorophenyl)-2-imidazoline hydrochloride as a residue.

To a stirred solution of 4.6 parts of 2-amino-l-(2- chloroethyl)-5-(o-chlorophenyl)-2-imidazoline hydrochloride in i2 parts of methanol is added a solution of 0.725 parts of sodium in 12 parts of methanol. The whole is stirred and refluxed for 1 hr. 30 minutes. The reaction mixture is evaporated and to the residue is added 50 parts of water and a small amount of a ION sodium hydroxide solution. The product is extracted twice with 40 parts of methylene chloride. The combined extracts are dried, filtered and evaporated. The residue is converted into the hydrochloride salt in 2- propanol and diisopropylether. The salt is filtered off, washed with acetone and dried, yielding 5-(0-chlorophenyl)-2,3 ,5 ,fi-tetrahydro-ll-i-imidazo[1,2- alimidazole hydrochloride; m.p. 2l5222C.

EXAMPLE XV To a stirred solution of l0.7 parts of (i)-2,3,5,6-tet rahydro-Sphenyll H-imidazo( l,2-a]imidazole in parts of methanol is added a warm solution of 8.6 parts of (+)-tartaric acid in 20 parts of methanol. The whole is diluted with 80 parts of acetone and the product is allowed to crystallize. The precipitated fraction is filtered off [about 5.6 parts of crude (+)-2,3,5,6-tetrahydro-S -phenyll H-imidazo[ l ,2-a]imidazole (+)-tartrate a( 1% MeOl-l): +873) and set aside. The filtrate is evaporated in vacuo. The residue is dissolved in water and the free base is liberated. it is extracted with chloroform and the latter is dried and evaporated. The residue is dissolved in 28 parts of methanol and to this solution is added a warm solution of 5.7 parts of ()-tartaric acid in 60 parts of methanol. The product is allowed to crystallize. It is filtered off and recrystallized from a mixture of 8 parts of methanol and 16 parts of acetone till a constant rotation, yielding about 4.3 parts of (-)-2,3 ,5,6-tetrahydro-S-phenyll H-imidazo[ 1,2- a]imidazole()-tartrate; a( 1% MeOH): 89.97. A sample of 4.2 parts of ()-2,3,5,G-tetrahydro-S-phenyl- Iii-imidazo[ l,2-a]imidazole(-)-tartrate is dissolved in water and the free base is liberated. After extraction with chloroform, the latter is dried and evaporated. The residue is crystallized from acetone, yielding about 0.7 parts of ()-2,3,5,6-tetrahydro-5-phenyl-1H- imidazol l ,2-a]imidazole; m.p. l53.2C.; a( 1% MeOH): 2l 1.49". The free base together with the residue of the evaporated mother-liquor is converted into the hydrochloride salt yielding about 1.9 parts of 2,3,5,G-tetrahydro-S-phenyl-l H-imidazo[ 1,2- a]imidazole hydrochloride; m.p. 277.lC.; MeOH):-1l5.79.

The first precipitated product of about 5.6 parts which was set aside is crystallized from a mixture of 8 parts of methanol and 16 parts of acetone till constant rotation, yielding about 3.5 parts of (+)-2,3,5,6-tetrahydro-S-phenyl-l H-imidazo[ l ,2-alimidazole (+)tartrate, a (1% MeOH): +88.83, is dissolved in water and the free base is liberated. After extraction with chloroform, the latter is dried and evaporated. The residue is crystallized from acetone, yielding about 1 part of (+)-2,3,5,6-tetrahydro-5-phenyl-ll-limidazoI l,2a]imidazole; m.p. 152.6C.; a (1% MeOH): +2 I 4.4 1. The free base together with the residue of the evaporated mother-liquor is converted into the hydrochloride salt in 2-propanol, yielding about 1.5 parts of (+)-2,3,5 ,6-tetrahydro-5-phenyl-l H- imidazo[ l ,2-a]imidazole hydrochloride; m.p. 277.3C.; i1(l% MeOi-l): +l l4.42.

EXAMPLE XVl The procedure of Example X may be followed to prepare the 2,3,5,6,7,8-hexahydro-3-Ar-imidazo[l,2- a]pyrimidines of formula (I). For example, by substituting an equivalent quantity of the 4-Br-, 4-Me-, 4-Et-, 3,4-diClderivative of a-(aminomethyUbenzyl alcohol for the ring-unsubstituted benzyl alcohol used therein, the following respective products are obtained:

3-(4-bromophenyl)-2,3,5,6,7,8-hexahydroimidazo[ l ,2-alpyrimidine; 2,3,5,6,7,8-hexahydro-3-(4-methylphenyl)- imidazo[ l,2-a]pyrimidine; 3-(4-ethylphenyl)-2,3,5,6,7,8-hexahydroimidazo[ l,2-a]pyrimidine; and 3-(3,4-dichlorophenyl)-2,3,5,6,7,8-hexahydroimidaso[ l ,2-a]pyrimidine.

EXAMPLE XVII EXAMPLE XVlll The procedure of Example Xll may be followed to prepare the 2,3,5,6,7,8-hexahydro-5-Ar-imidazo-]l ,2- a]pyrimidines of formula (I). For example, by substituting an equivalent amount of the 4-Cl-, 4-Meand 3,4-di-Cl derivatives of a-(2aminoethyl)benzyl alcohol for the ring-unsubstituted benzyl alcohol used therein, the following respective products are obtained:

5-(4-chlorophenyl)-2,3,5,6,7,8-hexahydro-imidazo- [1,2-a1pyrimidine; 2,3,5,6,7,8-hexahydro-5-(4-methylphenyl)-imidazo- [l,2-a]pyrimidine; and 5-(3,4-dichlorophenyl)-2,3,5,6,7,8-hexahydroimidazo-[ l ,2-a]pyrimidine.

EXAMPLE XIX The procedure of Example Xlll may be followed to prepare the 3,4,6,7,8,9-hexahydro-6-Ar-2H- pyrimido[l,2-a]pyrimidines of formula (I). For example, by substituting an equivalent amount of the 4-Br-, 4-Me-, and 3,4-di-Clderivatives of a-(2aminoethyl)- benzyl alcohol for the ring-unsubstituted benzyl alcohol used therein, the following respective products are obtained:

6-(4-bromophenyl)-3,4,6,7,8,9-hexahydro-2H- pyrimido[ l ,2-a]pyrimidine; 3,4,6,7,8,9-hexahydro-6-(4-methylphenyl)-2H- pyrimido-[ l,2-a]pyrimidine; and 6-(3,4-dichlorophenyl)-3,4,6,7,8,9-hexahydro-2H- pyrimido[ l ,2-a]pyrimidine. We claim:

1 A member l d from th group f compounds and the therapeutically active acid addition salts having the formula: thefeOf, Whereifli R is a member selected from the group consisting of A hydrogen and benzyl; and

5 Ar is a member selected from the group consisting of N phenyl, loweralkylphenyl, halophenyl and dihalophenyl.

A 2. 3,4,6,7,8,9-Hexahydro-6-phenyl-2H- pyrimido[ l ,2-a]pyrimidine. R 10 :v 1|: a:

UNITED STATES PATENT AND TRADEMARK OFFICE PATENT NO.

DATED tNVENTOR(S) CERTIFICATE OF CORRECTION December 9, 1975 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[SEAL] In Column 1, line 61, "text-butyl" should read tert-butyl In Column 3, line 22, "methyl alkyl halide" should read aroyl alkyl halide In Column 4, line 19 "zero of 1'' should read zero or 1 In Column 7, line 24 "exophtalmia" should read exophthalmia In Column 10, line 35, "Z-imidazoline-Z" should read Z-imidazolin-Z Arrest:

RUTH C. MASON Attesting Officer LUTRELLE F. PARKER Acting Commissioner of Patents and Trademarks 

1. A MEMBER SELECTED FROM THE GROUP OF COMPOUNDS HAVING THE FORMULA:
 2. 3,4,6,7,8,9-Hexahydro-6-phenyl-2H-pyrimido( 1,2-a)pyrimidine. 